Optimized sports article

ABSTRACT

Embodiments of the invention concerns a method of designing a sports article, including: (a) scanning at least one body part of at least a first person; (b) creating a first digital model of the body part of the first person; (c) creating a digital model of the sports article; (d) digitally arranging the digital model of the sports article on the first digital model of the body part, while allowing the digital model of the sports article to stretch digitally and (e) digitally modifying at least one property of the digital model of the sports article based on the first digital model of the body part and the digital model of the sports article.

FIELD OF THE INVENTION

The present invention relates to optimized methods of designing andproducing a sports article, especially a swimming cap.

BACKGROUND OF THE INVENTION

An accurate fit of a sports article, in particular sports apparel orfootwear, is particularly important as it may strongly affect theperformance of an athlete. For example, a sports shoe that does not fitproperly would not allow an athlete to make the most of their ability.

A poor fit may also lead to an increased drag. This is particularlyimportant for sports apparel, for example a swimming cap. Many swimmingcaps wrinkle or bulge at the top, which increases the drag during a raceor training and thus may hinder a top performance. Moreover, swimmingcaps as known in the art sometimes flick up around the ears or movearound on a wearer's head. This is a particular problem for athleteswith long hair, where the fit is frequently poor. In practice, manyathletes wear two caps rather than just one to overcome some of theseproblems. However, this is an inconvenience for the athlete, which addsunnecessary weight and may increase the drag experienced duringswimming. Another common problem experienced by many athletes is thatswimming caps tend to exert an upwards pull on the skin of a wearer,leading to discomfort and often forcing an athlete to readjust theposition of the swimming cap.

WO 2010/088459 A2 relates to a swim cap, which includes a shell forminga concave region terminating at a circumferential rim, and a resilientmargin secured to the shell along the circumferential rim.

WO 01/39051 A2 relates to a method for selecting a product and adaptinga product to the measurements of a consumer by detecting themeasurements of said consumer by means of a scanner. Pre-producedproducts are fitted by measuring the real human body by means of athree-dimensional (3D) scanning and processing the detected data forproducing a virtual body.

However, the methods known in the art for improving the fit of sportsarticle are insufficient to overcome the problems outlined above.

It is therefore an object of embodiments of the present invention toprovide a method of designing a sports article that allows an improvedfit compared with methods known in the art. It is a further object ofembodiments of the present invention to provide a swimming cap with animproved fit, that is comfortable to wear, avoids or reduces wrinkles atthe top, and stays in position even during sudden movements such as atumble turn.

BRIEF SUMMARY OF THE INVENTION

The first object is accomplished by the teachings of claim 1, inparticular by a method of designing a sports article, comprising:

-   -   (a) scanning at least one body part of at least a first person;    -   (b) creating a first digital model of the body part of the first        person;    -   (c) creating a digital model of the sports article;    -   (d) digitally arranging the digital model of the sports article        on the first digital model of the body part, while allowing the        digital model of the sports article to stretch digitally; and    -   (e) digitally modifying at least one property of the digital        model of the sports article based on the first digital model of        the body part and the digital model of the sports article.

The inventors have realised that it is not only the size and measures ofa sports article that determine its fit, but also its stretch. This istrue in particular for sports articles that require a tight fit toreduce the drag in water or their air resistance, for example, aswimming cap, a running shirt, running shorts, cycling outfit, etc.Therefore, an important aspect of embodiments of the present inventionis to allow the digital model of the sports article to stretchdigitally. This may optionally take into account certain materialproperties of the sports article, such as its elasticity. For example,if a circumference of the body part is C_(B) and an unstretchedcorresponding circumference of the sports article is C_(S), thenallowing the sports article to stretch digitally may comprise scalingthe corresponding circumference of the sports article by a factor ofC_(B)/C_(S).

This method may be used to produce a customised sports article for anindividual customer, or the method may be used to produce a sportsarticle in large quantities based on the first digital model of the bodypart of the first person. It is important to understand that the sizeand shape of the body part may vary from person to person and thereforethe digital model, once modified, may have a custom shape that variesfrom person to person. However, the methods described herein allow anoptimal fit to be achieved for many sizes and shapes of the body part.

The method may further comprise: scanning the body part of a secondperson;

creating a second digital model of the body part of the second person;creating an average digital model of the body part based on an averageof the first digital model and the second digital model; digitallyarranging the digital model of the sports article on the average digitalmodel of the body part, allowing the digital model of the sports articleto stretch digitally, wherein digitally modifying the property of thedigital model of the sports article is based on the average digitalmodel of the body part and the digital model of the sports article.

Therefore, the method of designing a sports article, may comprise: (a1)scanning at least one body part of at least a first person; (a2)scanning the body part of a second person; (b1) creating a first digitalmodel of the body part of the first person; (b2) creating a seconddigital model of the body part of the second person; (c) creating anaverage digital model of the body part based on an average of the firstdigital model and the second digital model; (d) creating a digital modelof the sports article; (e) digitally arranging the digital model of thesports article on the average digital model of the body part, allowingthe digital model of the sports article to stretch digitally; and (f)digitally modifying at least one property of the digital model of thesports article based on the average digital model of the body part andthe digital model of the sports article.

In other words, rather than using just a first digital model of a bodypart of the first person, an average of the first digital model of thebody part of the first person and the second digital model of the bodypart of the second person is used. It is possible that the body part ofthree or more persons, for example a plurality of persons, is scannedand the corresponding digital models are used for creating an averagedigital model. It is to be understood that the same body part is scannedin any case, e.g. if a right hand is scanned for a first person, theright hand of a second, third, fourth person etc. is scanned. This wayit is possible to create an accurate digital model of the body part thatallows designing a sports article that fits well for a group of people,for example for a group of swimming athletes.

For example, in order to provide an optimal fit of the swimming cap fora group of swimmers, it is advantageous to understand the geometry ofthe swimmers' heads. This can be achieved by creating an average digitalmodel of the head, which comprises scanning the head of multipleswimmers and performing a statistical analysis of the head scans. Oneexemplary way to perform this is by a non-rigid registration process,which digitally applies a common template mesh to all head scaninstances and by obtaining a set of meshes corresponding to the multiplehead scans. Each mesh of the set of meshes has the same topology andnumber of vertices but with a different geometry and shape correspondingto the respective original scan. The set of meshes then allows todirectly and easily compare the head scans and to perform statisticaloperations such as computation of averages or standard deviations. Anaverage model of the multiple head scans can thus be generated.Alternatively, any suitable method for generating a 3D geometry may beused here.

Scanning at least one body part may comprise using optical means, forexample a camera, a stereo-camera system, a structured light scanning,or laser scanning, in order to create a three-dimensional digital modelof the at least one body part. One example is using ARTEC 3D EVA.

Scanning at least one body part may comprise providing at least twocameras to obtain a three-dimensional image of the body part. By usingtwo cameras, arranged at different positions, it is possible toconstruct a three-dimensional image of the body part without having tomove the body part. It may be difficult to control accurately whilemoving the body part, for example there may be a certain degree oftranslation, even if only rotation is required for a certain imagesequence. Therefore, by using at least two cameras, arranged atdifferent positions, it is possible to construct a more accuratethree-dimensional image of the body part.

Alternatively, a three-dimensional image of the body part may beobtained using only one camera with designed image processing toolsand/or additional information from supplementary motion sensors such asaccelerometers on a portable electronic device.

The body part may be a head and the sports article may be a swimmingcap.

Swimming caps known in the art tend to wrinkle or bulge at the top. Thisincreases the drag experienced by an athlete and may hinder a topperformance. Therefore, the method according to embodiments of thepresent invention is particularly advantageous if the body part is ahead and the sports article is a swimming cap.

The property of the digital model of the sports article may comprise acircumference of the sports article; and wherein digitally modifying thecircumference comprises: digitally modifying the circumference suchthat, when digitally arranging the digital model of the sports articleon the first digital model of the body part or the average digital modelof the body part, the circumference of a first portion of the digitalmodel of the sports article stretches by a first fraction and thecircumference of a second portion of the digital model of the sportsarticle stretches by a second fraction. It is to be understood thatdigitally modifying the circumference means, digitally modifying theunstretched circumference, i.e. digitally modifying is not the same asdigitally stretching since in the latter case the circumference wouldincrease but the unstretched circumference would not increase.Unstretched means, that no force is deliberately applied to stretch thecircumference.

An important insight of the inventors is that the fit can be improvedsignificantly, if the circumference of a first portion of the sportsarticle stretches by a first fraction and the circumference of a secondportion of the sports article stretches by a second fraction. In otherwords, there are differences between the first portion and the secondportion in the tightness of the fit of the sports article.

The first portion may be a top portion and the second portion may be abottom portion of the sports article and the first fraction may besmaller than the second fraction. In other words, the sports article mayhave a tighter fit in a bottom portion than in a top portion. In thepresent context, a top portion is arranged closer to an apex of thesports article, e.g. the swimming cap, than a bottom portion. Theinventors have found, that this arrangement improves the fit of thesports article and for example reduces the formation of wrinkles andbulges at the top of a swimming cap.

The first fraction may be between 0% and 10% and the second fraction maybe between 20% and 50%, preferably between 25% and 35%. The inventorshave found that a large second fraction, i.e. a large stretch, improvesthe fit of the sports article and for example reduces the formation ofwrinkles and bulges at the top of a swimming cap. However, if the secondfraction is too large, the sports article becomes uncomfortable to wear.Moreover, the first fraction is preferably relatively small, in order toimprove the fit of the sports article. It is to be understood that ifthe first fraction is, for example, 30%, the stretched circumference ofthe first portion is 1.3 times the unstretched circumference of thefirst portion of the digital model of the sports article.

The property of the digital model of the sport articles may comprise ashape of the sports article. The shape of the sports article cruciallydetermines its fit. The method according to embodiments of the presentinvention is ideally suited for digitally modifying the shape of thedigital model of the sports article based on the digital model of thebody part and the digital model of the sports article. Therefore, animproved fit of the sports article may be achieved.

For example, the sports article may be a swimming cap and modifying theshape of the digital model of the swimming cap may comprise, creatingtwo overhang portions arranged symmetrically on either side of a spineof a wearer and a recess arranged in proximity to the spine. An overhangportion, in the present context, is any portion of the swimming cap thatprotrudes from a surrounding edge of the swimming cap. A recess, in thepresent context is an analogous indentation from the surrounding edge ofthe swimming cap.

A surrounding edge is an imaginary edge of the swimming cap defined byan edge in a forehead portion of the swimming cap and extended aroundthe entire circumference of the swimming cap. A geometrically-equivalentdefinition of an overhang portion and a recess can be made in respect ofa plane defined by three distinct non-collinear points on an edge of theswimming cap in a forehead portion of the swimming cap. The planedefines a reference with respect to which the overhang portions protrudeand with respect to which the recess represents an indentation.

In other words, an overhang portion protrudes with respect to asurrounding edge and a recess represents an indentation with respect tothe surrounding edge, wherein the surrounding edge is an imaginary edgeof the swimming cap defined by an edge of a forehead portion of theswimming cap and extended around the entire circumference of theswimming cap.

Or equivalently, an overhang portion protrudes with respect to a planeand a recess represents an indentation with respect to the plane,wherein the plane is defined by three distinct non-collinear points onan edge of the swimming cap in a forehead portion of the swimming cap.

The inventors have found that two overhang portions arrangedsymmetrically on either side of a spine of a wearer and a recessarranged in proximity to the spine may improve the stability of theswimming cap on the head of an athlete.

The overhang portions may protrude from a surrounding edge, orequivalently the plane defined above, of the swimming cap by at least 1cm and the recess may represent an indentation from the surroundingedge, or equivalently the plane defined above, by at least 1 cm. Thisway, the stability of the fit of the swimming cap on the head of anathlete may be improved.

The digital model of the sports article and/or the first digital modelof the body part and/or the average digital model of the body part mayfurther comprise at least one material property of the sports articleand/or the body part. A material property in the present context is anyproperty of a material of the sports article and/or the body part apartfrom geometric properties such as a thickness, length, circumference,etc. It is to be understood that the property may also comprisegeometric properties such as a thickness, length, circumference, etc.

By including at least one material property of the sports article and/orthe body part in the corresponding digital model, it is possible tofurther improve the fit and comfort of the sports article.

The at least one material property may comprise an elastic modulus ofthe sports article.

The method may further comprise calculating at least one force on thebasis of the first digital model of the body part or the average digitalmodel of the body part and the digital model of the sports article, andwherein digitally modifying at least one property of the digital modelof the sports article may be at least partially based on the calculatedforce.

For a given stretch, the force exerted by the sports article on the bodypart depends on the elastic modulus of the sports article. Therefore, todesign a sports article with a comfortable fit, it is advantageous toinclude an elastic modulus of the sports article in the digital model.

The force may be an upwards-pulling shear force, or a vertical shearforce more generally, and digitally modifying at least one property ofthe digital model of the sports article may comprise reducing theupwards-pulling shear force, or the vertical shear force. The inventorshave found, that a vertical shear force, e.g. an upwards-pulling shearforce, is uncomfortable for the athlete as it pulls on the skin, forexample the skin on the forehead of the athlete, or on the athlete'shair. Moreover, an upwards-pulling shear force may lead to a poor fit,especially during dynamic movement, such that the swimming cap mayconsequently slide upwards on the head of the athlete.

It is therefore advantageous to reduce the vertical shear force, e.g.the upwards-pulling shear force as achieved by the sports article andthe method of embodiments of the present invention.

The force may be calculated on the basis of a finite-element analysis. Afinite-element analysis is any method that subdivides a space into anumber of finite elements in order to solve an underlying set ofequations, for example an underlying set of partial differentialequations. Each element is assigned certain properties e.g. an elasticmodulus. Numerous types of finite-element analysis are suitable.

Digitally modifying at least one property of the digital model of thesports article may comprise digitally modifying a thickness of thesports article.

The thickness is an important parameter for determining the fit andstability of the sports article. For example, the inventors have foundthat a swimming cap with a uniform thickness leads to a large verticalshear force and in particular an upwards-pulling shear force. Theswimming cap will thus tend to “pull itself off the head” of theathlete. The upwards-pulling shear force can be reduced by a swimmingcap comprising: a main body comprising a first thickness; and a rimportion, arranged around a rim of the swimming cap, comprising a secondthickness; wherein the first thickness is smaller than the secondthickness.

Embodiments of the invention further concerns a method of producing asports article comprising:

-   -   (a) creating a design of a sports article by any method        described herein; and (b) producing the sports article according        to the design. Thus, a sports article with an improved fit may        be obtained.

Producing the sports article may comprise injection molding or slushmolding the sports article. Injection molding and slush molding aresimple and efficient ways of producing large quantities of a sportsarticle.

Embodiments of the invention further concerns a swimming cap comprising:a main body comprising a first thickness; a rim portion, arranged arounda rim of the swimming cap, comprising a second thickness; and twooverhang portions (19) arranged symmetrically on either side of a spineof a wearer and a recess (20) arranged in proximity to the spine. Theterms overhang portion and recess have already been defined herein.

The inventors have found that two overhang portions arrangedsymmetrically on either side of a spine of a wearer and a recessarranged in proximity to the spine may improve the stability of theswimming cap on the head of an athlete and reduce a vertical shear forceand in particular an upwards-pulling shear force on the cap. Therefore,the swimming cap according to embodiments of the present inventionprovides a better and more comfortable fit than swimming caps known inthe art.

The first thickness may be different from the second thickness. However,the first and the second thickness may also be identical.

The first thickness may be smaller than the second thickness. Theinventors have found that a swimming cap with a uniform thickness maylead to a large vertical shear force and in particular anupwards-pulling shear force. The swimming cap may tend to “pull itselfoff the head” of the athlete. The vertical shear force, in particularthe upwards-pulling shear force can be reduced further by a swimming capcomprising: a main body comprising a first thickness; and a rim portion,arranged around a rim of the swimming cap, comprising a secondthickness; wherein the first thickness is smaller than the secondthickness.

The first thickness may be between 0.2 and 0.6 mm, preferably between0.3 and 0.5 mm. The smaller the first thickness, the smaller is avertical shear force, especially an upwards-pulling shear force.However, the first thickness cannot be too small for two reasons. First,the swimming cap needs to have a certain minimum first thickness toensure sufficient stability. Secondly, for a small first thickness, thehair of an athlete creates indentations on the outside of the swimmingcap, which may lead to turbulence during swimming and increase the dragexperienced by the athlete. The inventors have found, that the givenrange provides a preferable balance between these factors, allowing anideal fit, good stability, and low drag.

The second thickness may be between 1.5 and 2.5 mm, preferably between1.5 and 2 mm. The greater the second thickness, the lower is a verticalshear force and especially an upwards-pulling shear force. However, ifthe second thickness is too large, the drag experienced by an athlete isincreased.

The main body may comprise a first material and the rim portion may alsocomprise the first material. The swimming cap may be formed fromessentially a single material. “Essentially” means in this contextregardless of fluctuations and manufacturing imperfections, for exampledue to impurities. This allows for a particularly simple construction,for example by injection molding or slush molding, of the swimming cap.

A width of the rim portion may vary around the rim between 10 mm and 30mm. The inventors have found that the variation in the width of the rimportion may further improve the balance between good fit and low drag.For example, the rim portion may have a smaller width in a front portionthan in a rear portion. A front portion, in the present context, is aportion of the swimming cap that is arranged on the forehead of anathlete during normal use. This way, the drag from the rim portion maybe reduced in a front portion, which is particularly important fordetermining the drag, while a wider rim portion in a rear portion mayimprove the fit of the swimming cap.

The main body and/or the rim portion may comprise a shore A hardness ofbetween 20 and 60, preferably between 20 and 50, most preferably between20 and 40. The inventors have found that a greater hardness reduces thedepth or height of indentations caused by the athlete's hair on theoutside of the swimming cap. This improves the drag experienced by theathlete. However, if the swimming cap is too hard, it is experienced asuncomfortable by an athlete. A good balance between these two factors isachieved in the hardness range specified above.

The surface of the main body and/or the rim portion may comprise atexture. The inventors have found, that a textured surface may lower thedrag experienced by an athlete wearing the swimming cap.

The overhang portions may protrude from a surrounding edge, orequivalently the plane defined herein, of the swimming cap by at least 1cm and the recess may represent an indentation from the surroundingedge, or equivalently the plane defined herein, by at least 1 cm. Thisway, the stability of the fit of the swimming cap on the head of anathlete may be improved.

The swimming cap may comprise neoprene, latex, and/or silicone. Thesematerials are durable and comfortable to wear. Neoprene, latex and/orsilicone, also known as polysiloxane, allow the hair of the athlete tobe kept dry since they are essentially waterproof. Essentiallywaterproof is to be understood that, even though the materialsthemselves are waterproof, some water may enter under the swimming capthrough voids or crevices formed especially around the edge of theswimming cap, for example due to the hair of the athlete.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, exemplary embodiments of the invention are describedwith reference to the figures.

FIG. 1A: shows a front view of an exemplary digital model of a body partand an exemplary digital model of a sports article according to thepresent invention.

FIG. 1B: shows a lateral view of the exemplary digital model of a bodypart and the exemplary digital model of a sports article of FIG. 1A.

FIG. 1C: shows a perspective view of the exemplary digital model of asports article of FIG. 1A.

FIG. 2A: shows a perspective view of an exemplary digital model of aswimming cap according to the present invention.

FIG. 2B: shows shear forces acting on the exemplary digital model of aswimming cap of FIG. 2A.

FIG. 2C: shows shear forces acting on the exemplary digital model of aswimming cap of FIG. 2A.

FIG. 2D: shows shear forces acting on the exemplary digital model of aswimming cap of FIG. 2A.

FIG. 3A: shows a front view of an exemplary swimming cap according tothe present invention.

FIG. 3B: shows a rear view of the exemplary swimming cap of FIG. 3A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following some embodiments of the invention are described indetail. It is to be understood that these exemplary embodiments can bemodified in a number of ways and combined with each other whenevercompatible and that certain features may be omitted in so far as theyappear dispensable.

FIGS. 1A-1C illustrate an exemplary method of designing a sports articleaccording to embodiments of the present invention.

The exemplary method of designing a sports article comprises: (al)scanning at least one body part of at least a first person; (a2)scanning the body part of a second person; (b 1) creating a firstdigital model (not shown in FIGS. 1A-1C) of the body part of the firstperson; (b2) creating a second digital model (not shown in FIGS. 1A-1C)of the body part of the second person; (c) creating an average digitalmodel of the body part 11 b based on an average of the first digitalmodel and the second digital model; (d) creating a digital model of thesports article 12; (e) digitally arranging the digital model of thesports article 12 on the average digital model of the body part 11 b,allowing the digital model of the sports article 12 to stretchdigitally; and (f) digitally modifying at least one property of thedigital model of the sports article 12 based on the average digitalmodel of the body part 11 b and the digital model of the sports article12.

FIG. 1A shows a front view of the exemplary average digital model of abody part 11 b, in this example a head, and an exemplary digital modelof a sports article 12, in this example a swimming cap. FIG. 1B shows acorresponding lateral view.

In this example, scanning at least one body part comprises providing atleast two cameras to obtain a three-dimensional image of the body part.This way, the three-dimensional first digital model of the body part andthe three-dimensional second digital model of the body part underlyingthe average digital model of the body part 11 b shown in FIGS. 1A-1Bwere obtained.

The property, which is modified, comprises a shape of the swimming cap.In this example, an initial length 13 of the swimming cap in a frontportion 21 is modified. The modified length 14 is longer than theinitial length 13 as shown in FIG. 1B. The front portion 21 may be aportion of the swimming cap that is arranged on the forehead of anathlete during normal use.

Referring to FIG. 1C, the property of the digital model of the sportsarticle 12 comprises a circumference of the swimming cap. Digitallymodifying the circumference comprises: digitally modifying thecircumference such that, when digitally arranging the digital model ofthe swimming cap 12 on the first digital model of the body part 11 a orthe average digital model of the body part 11 b, the circumference of afirst portion 15 of the digital model of the swimming cap 12 stretchesby a first fraction and the circumference of a second portion 16 of thedigital model of the swimming cap 12 stretches by a second fraction. Itis to be understood that digitally modifying the circumference means,digitally modifying the unstretched circumference, i.e. digitallymodifying is not the same as digitally stretching since in the lattercase the circumference would increase but the unstretched circumferencewould not increase.

In this example, the digital model of the swimming cap 12 also comprisesa third portion 17 and a fourth portion 18. The circumference of a thirdportion 17 of the swimming cap stretches by a third fraction and thecircumference of a fourth portion 18 of the swimming cap stretches by afourth fraction.

In this example, the first portion 15 is a top portion and the secondportion 16 is an intermediate portion of the swimming cap, and the firstfraction is smaller than the second fraction. The third portion 17 is alower intermediate portion and the fourth portion 18 is a bottom portionof the swimming cap. The second fraction is smaller than the thirdfraction, which, in turn, is smaller than the fourth fraction. It isalso possible that there are only a top portion and a bottom portion fora swimming cap. In this case, the first portion 15 and the secondportion 16 can be the same as a top portion, and the third portion 17and the fourth portion can be the same as a bottom portion.Alternatively, the top portion can include first to third portions15-17.

As an example, the first fraction is 10%, the second fraction is 20%,the third fraction is 30% and the fourth fraction is 40%.

In this example, modifying the shape of the digital model of theswimming cap further comprises creating two overhang portions 19arranged symmetrically on either side of a spine of a wearer and arecess 20 arranged in proximity to the spine. The overhang portions 19protrude from a surrounding edge (omitted for clarity, shown in FIG. 2A)of the digital model of the swimming cap by 1.5 cm and the recess 20represents an indentation from the surrounding edge by 3 cm.

In particular, in order to provide an optimal fit of the swimming capfor a group of swimmers, there is a need to understand the geometry ofthe swimmers' heads. This can be achieved by creating an average digitalhead model of the swimmers, which comprises scanning the head ofmultiple swimmers and performing a statistical analysis of the headscans. One exemplary way to perform this is by a non-rigid registrationprocess, which digitally applies a common template mesh to all head scaninstances and obtains a set of meshes corresponding to the multiple headscans. Each mesh of the set of meshes has the same topology and numberof vertices but with various geometry and shape corresponding to therespective original scan. The set of meshes then allows to directly andeasily compare the head scans and to perform statistical operations suchas computation of averages or standard deviations. An average model ofthe multiple head scans can thus be generated. Alternatively, anysuitable method for generating a 3D geometry may be used here.

FIGS. 2A-2D illustrate another aspect of embodiments of the presentinvention. FIG. 2A shows an exemplary digital model of a swimming cap.

The exemplary digital model of the swimming cap 12 comprises: a mainbody 23 comprising a first thickness; and a rim portion 24, arrangedaround a rim of the swimming cap, comprising a second thickness; and twooverhang portions 19 arranged symmetrically on either side of a spine ofa wearer and a recess 20 arranged in proximity to the spine.

The overhang portions 19 protrude from a surrounding edge 29 of thedigital model of the swimming cap 12. The recess 20 is an analogousindentation from the surrounding edge 29 of the digital model of theswimming cap 12.

The surrounding edge 29 is an imaginary edge of the swimming cap definedby a forehead portion of the swimming cap and extended around the entirecircumference of the digital model of the swimming cap 12. Ageometrically-equivalent definition of an overhang portion and a recesscan be made in respect of a plane defined by three distinctnon-collinear points 30 a-30 c on an edge of the digital model of theswimming cap in a forehead portion of the digital model of the swimmingcap 12. The plane defines a reference with respect to which the overhangportions protrude and with respect to which the recess represents anindentation.

The recess 20 is arranged in a rear portion 22 opposite of a frontportion 21. The overhang portions 19 protrude from a surrounding edge 29of the digital model of the swimming cap by 1.5 cm and the recess 20represents an indentation from the surrounding edge 29 by 3 cm, asindicated by the dotted line.

In this example, the first thickness is smaller than the secondthickness.

In this case, the digital model of the swimming cap 12 further comprisesat least one material property of the swimming cap. The at least onematerial property comprises an elastic modulus of the swimming cap. Theexemplary digital model of the swimming cap 12 is for a swimming capmade from silicone and therefore the elastic modulus is the elasticmodulus of silicone. In this case the elastic modulus, also known asYoung's modulus could be between 2-12 MPa.

As illustrated in FIGS. 2B-2D, the method further comprises calculatingat least one force on the basis of the first digital model of the bodypart 11 a and the digital model of the sports article 12. Digitallymodifying the property of the digital model of the sports article 12 isat least partially based on the calculated force. The force is avertical shear force and in particular an upwards-pulling shear force,and digitally modifying the property of the digital model of the sportsarticle 12 comprises reducing the upwards-pulling shear force. The forceis calculated on the basis of a finite-element analysis.

FIGS. 2B-2D show the vertical shear force and in particular theupwards-pulling shear force calculated for three different digitalmodels of the swimming cap using the same first digital model of thebody part 11 a, i.e. the head.

The digital model of the swimming cap shown in FIG. 2B has a main body(such as main body 23 shown in FIG. 2A) with a uniform thickness of 0.8mm and a rim portion (such as rim portion 24 shown in FIG. 2A) with athickness of 2 mm. FIG. 2B shows that a low-force region 26 is locatedjust below the ear of the first digital model of the head, andmedium-force regions 27 are located in proximity to the os temporale andthe os occipitale. High-force regions 28 are located in proximity to theos frontale and over the ear. Reference numeral 25 indicates a“zero-force region” in which the calculated forces are below apredetermined threshold value.

The digital model of the swimming cap shown in FIG. 2B therefore overallleads to quite substantial vertical shear forces and in particularupwards-pulling shear forces that would act to pull the swimming cap offthe head of an athlete and may lead to substantial discomfort for theathlete. It should be noted that a digital model of a swimming cap witha uniform thickness, i.e. a swimming cap without a rim portion 24, woulddisplay far greater vertical shear forces and in particularupwards-pulling shear forces.

The digital model of the swimming cap shown in FIG. 2C has a main body(such as main body 23 shown in FIG. 2A) with a uniform thickness of 0.6mm and a rim portion (such as rim portion 24 shown in FIG. 2A) with athickness of 2 mm. FIG. 2C shows that low-force region 26 s are locatedjust below the ear of the first digital model of the head and inproximity to the os temporale. A medium-force region 27 is located inproximity to the os frontale. Reference numeral 25 indicates a“zero-force region” in which the calculated forces are below apredetermined threshold value.

The digital model of the swimming cap shown in FIG. 2C therefore overallleads to significantly-reduced vertical shear forces and in particularupwards-pulling shear forces compared with the digital model of theswimming cap shown in FIG. 2B.

The digital model of the swimming cap shown in FIG. 2D has a main body(such as main body 23 shown in FIG. 2A) with a uniform thickness of 0.4mm and a rim portion (such as rim portion 24 shown in FIG. 2A) with athickness of 2 mm. FIG. 2D shows that a low-force region 26 is locatedjust below the ear of the first digital model of the head 11 a.Reference numeral 25 indicates a “zero-force region” in which thecalculated forces are below a predetermined threshold value.

The digital model of the swimming cap shown in FIG. 2D therefore overallleads to almost no vertical shear forces and in particular almost noupwards-pulling shear forces, therefore leading to an excellent andstable fit and a comfortable wearing experience.

FIGS. 3A-3B show an exemplary swimming cap 32 according to embodimentsof the present invention. The swimming cap 32 is arranged on a dummy 31,which is a physical model of an average digital model of a head 11 b asdescribed herein, for example with reference to FIGS. 1A-1C. FIG. 3Ashows a front view, while FIG. 3B shows a rear view.

The swimming cap 32 comprises: a main body 23 comprising a firstthickness; and a rim portion 24, arranged around a rim of the swimmingcap 32, comprising a second thickness; and two overhang portions 19arranged symmetrically on either side of a spine of a wearer and arecess 20 arranged in proximity to the spine.

The overhang portions 19 protrude from a surrounding edge 29 of theswimming cap 32. The recess 20 is an analogous indentation from thesurrounding edge 29 of the swimming cap 32.

The surrounding edge 29 is an imaginary edge of the swimming cap definedby a forehead portion of the swimming cap and extended around the entirecircumference of the digital model of the swimming cap 12. Ageometrically-equivalent definition of an overhang portion and a recesscan be made in respect of a plane defined by three distinctnon-collinear points 30 a-30 c on an edge of the swimming cap 32 in aforehead portion of the swimming cap 32. The plane defines a referencewith respect to which the overhang portions 19 protrude and with respectto which the recess 20 represents an indentation.

In this example, the first thickness is smaller than the secondthickness.

The first thickness is 0.4 mm and the second thickness is 2 mm. The mainbody 23 comprises a first material and the rim portion 24 also comprisesthe first material. In this case, the main body 23 and the rim portion24 are made from silicone using slush molding.

A width of the rim portion 24 varies around the rim between 10 mm and 30mm. The inventors have found that the variation in the width of the rimportion 24 may further improve the balance between good fit and lowdrag. In this example, the rim portion 24 has a smaller width in a frontportion 21 than in a rear portion 22.

The main body 23 and the rim portion 24 comprise a shore A hardness of40.

Although in this example the surface of the main body 23 and/or the rimportion 24 does not comprise a texture, in other examples the surface ofthe main body 23 and/or the rim portion 24 may comprise a texture.

The overhang portions 19 protrude from a surrounding edge 29 of theswimming cap 32 by 1 cm and the recess 20 represents an indentation fromthe surrounding edge 29 by 1 cm.

REFERENCE NUMERALS

-   -   11 a: first digital model of the body part    -   11 b: average digital model of the body part    -   12: digital model of the sports article    -   13: initial length    -   14: modified length    -   15: first portion    -   16: second portion    -   17: third portion    -   18: fourth portion    -   19: overhang portion    -   20: recess    -   21: front portion    -   22: rear portion    -   23: main body    -   24: rim portion    -   25: zero-force region    -   26: low-force region    -   27: medium-force region    -   28: high-force region    -   29: surrounding edge    -   30 a,30 b,30 c: point    -   31: dummy    -   32: swimming cap

What is claimed is:
 1. A method of designing a sports article,comprising: (a) scanning at least one body part of at least a firstperson; (b) creating a first digital model of the body part of the firstperson; (c) creating a digital model of the sports article; (d)digitally arranging the digital model of the sports article on the firstdigital model of the body part, while allowing the digital model of thesports article to stretch digitally; and (e) digitally modifying atleast one property of the digital model of the sports article based onthe first digital model of the body part and the digital model of thesports article.
 2. The method according to claim 1, further comprising:scanning the body part of a second person; creating a second digitalmodel of the body part of the second person; creating an average digitalmodel of the body part based on an average of the first digital modeland the second digital model; digitally arranging the digital model ofthe sports article on the average digital model of the body part,allowing the digital model of the sports article to stretch digitally,wherein digitally modifying the property of the digital model of thesports article is based on the average digital model of the body partand the digital model of the sports article.
 3. The method according toclaim 1, wherein the body part is a head and the sports article is aswimming cap.
 4. The method according to claim 1, wherein the propertyof the digital model of the sports article comprises a circumference ofthe sports article; and wherein digitally modifying the circumferencecomprises: digitally modifying the circumference such that, whendigitally arranging the digital model of the sports article on the firstdigital model of the body part: the circumference of a first portion ofthe digital model of the sports article stretches by a first fraction;the circumference of a second portion of the digital model of the sportsarticle stretches by a second fraction.
 5. The method according to claim4, wherein the first portion is a top portion and the second portion isa bottom portion of the sports article; and wherein the first fractionis smaller than the second fraction.
 6. The method according to claim 5,wherein the first fraction is between 0% and 10% and the second fractionis between 20% and 50%.
 7. The method according claim 1, wherein thedigital model of the sports article and/or the first digital model ofthe body part further comprises at least one material property of thesports article and/or the body part.
 8. The method according claim 2,wherein the digital model of the sports article and/or the first digitalmodel of the body part and/or the average digital model of the body partfurther comprises at least one material property of the sports articleand/or the body part.
 9. The method according to claim 7, wherein the atleast one material property comprises an elastic modulus of the sportsarticle.
 10. The method according to claim 1, further comprisingcalculating at least one force on the basis of the first digital modelof the body part and the digital model of the sports article, andwherein digitally modifying the property of the digital model of thesports article is at least partially based on the calculated force. 11.The method according to claim 2, further comprising calculating at leastone force on the basis of the average digital model of the body part andthe digital model of the sports article, and wherein digitally modifyingthe property of the digital model of the sports article is at leastpartially based on the calculated force.
 12. The method according toclaim 10, wherein the force is a vertical shear force, and whereindigitally modifying at least one property of the digital model of thesports article comprises reducing the vertical shear force.
 13. Themethod according to claim 10, wherein digitally modifying at least oneproperty of the digital model of the sports article comprises digitallymodifying a thickness of the sports article.
 14. A method of producing asports article comprising: (a) creating a design of a sports articleaccording to claim 1; and (b) producing the sports article according tothe design.
 15. A swimming cap comprising: a main body comprising afirst thickness; a rim portion, arranged around a rim of the swimmingcap, comprising a second thickness; and two overhang portions arrangedsymmetrically on either side of a spine of a wearer and a recessarranged in proximity to the spine.
 16. The swimming cap according toclaim 15, wherein the first thickness is smaller than the secondthickness.
 17. The swimming cap according to claim 15, wherein the firstthickness is between 0.2 and 0.6 mm.
 18. The swimming cap according toclaim 15, wherein the second thickness is between 1.5 and 2.5 mm. 19.The swimming cap according to claim 15, wherein the main body comprisesa first material and the rim portion also comprises the first material.20. The swimming cap according to claim 15, wherein a width of the rimportion varies around the rim between 10 mm and 30 mm.
 21. The swimmingcap according to claim 15, wherein the main body and/or the rim portioncomprises a shore A hardness of between 20 and
 60. 22. The swimming capaccording to claim 15, wherein the overhang portions protrude from asurrounding edge of the swimming cap by at least 1 cm and the recessrepresents an indentation from the surrounding edge by at least 1 cm.